//201902104003邵潇漩
package util;

public class Pagination {
    public Pagination(int pageSize,int pageNo){
        //防止错误赋值
        if(pageSize>0){
            this.pageSize=pageSize;
        }else {
            this.pageSize=5;
        }
        if(pageNo>0){
            this.pageNo=pageNo;
        }else {
            this.pageNo=1;
        }
    }
    //返回LIMIT子句
    public String toLimitClause(int totalNum){
        //向前台提供元组总数(totalNum为0不是错误)
        this.totalNum=totalNum;
        //偏移量
        int offset=(this.pageNo-1)*this.pageSize;
        //输出LIMIT子句，注意关键字两端的空格
        return " LIMIT "+offset+" ,"+this.pageSize;
    }
    //如果没有get方法，fastjson将无法读取对象属性
    public int getPageSize(){
        return pageSize;
    }
    public int getPageNo(){
        return pageNo;
    }
    public int getTotalNum(){
        return totalNum;
    }

    //每页的元组数
    private int pageSize=5;
    //页号
    private int pageNo=1;
    //元组总数
    private int totalNum=1;
}
